<img src="pic_bulboff.gif" id="pic"  onclick="kaiGuan()"/>
<script>
 var i = 1;
function kaiGuan()
{
  if(i==1)
 {
   pic.src="pic_bulbon.gif";
   i=0;	
 }else
{
  pic.src="pic_bulboff.gif";
  i=1;
 }
 
} 
</script>
